The method for converting time-varying signals (Aj) acquired over a large number of recording channels comprises the steps of: acquiring all the signals (Aj) for an acquisition time that is equal for all the signals computing, by means of the Fourier transform, the power spectrum (Fij) of each signal (Aj) in consecutive time windows (Wi) memorising the power spectrum (Fij) of each signal (Aj) in each time window (Wi) attributing and memorising a correlation between an intensity value of a colour and the value of the integral (Hij,k) of the power spectrum (Fij) of any signal (Aj) in any time window (Wi), within a given neighbourhood of any frequency of interest (k) of a. predefined interval of frequencies of interest generating a map with cells (Cf,g), wherein each signal (Aj) in each time window (Wi) has associated with it a corresponding cell (Cf,g) of the map, and in which, when any frequency (k) of interest is selected, the value of the integral (Hi j,k) of the memorised power spectrum (Fij) of each signal (Aj) in each time window (Wi), within the given neighbourhood of the selected frequency of interest (k), is computed in order to attribute the colour intensity to each of the cells (Cf,g) of the map.La présente invention concerne un procédé de conversion de signaux variant dans le temps (Aj) acquis dans un grand nombre de canaux denregistrement, comprenant les étapes suivantes : acquisition de tous les signaux (Aj) pour un temps dacquisition égal pour tous les signaux calcul, au moyen de la transformée de Fourier, du spectre de puissance (Fij) de chaque signal (Aj) dans des fenêtres de temps consécutives (Wi) mémorisation dudit spectre de puissance (Fij) de chaque signal (Aj) dans chaque fenêtre de temps (Wi) attribution et mémorisation dune corrélation entre une valeur dintensité dune couleur et la valeur de lintégrale (Hij,k) du spectre de puissance (Fij) de nimporte quel signal (Aj) dans nimporte quelle fenêtre de temps (Wi), dans un voisinage donné de nimpo
